Commitments and Contingencies (Details) (USD $)	12 Months Ended
Dec. 31, 2011 month year
Company's commitments for agreements with take or pay or other similar commitment provisions
Outstanding construction-related commitments	$ 32,800,000
Number of other steel manufacturing companies also served with a class action antitrust complaint	8
Number of the complaints not brought on behalf of steel product purchasers	1
Commitments with suppliers "take or pay"
Commitment and contingencies
Commodity actual usage period (in months)	24
Commodity transportation requirements period (in years)	9
Company's commitments for agreements with take or pay or other similar commitment provisions
2012	122,705,000
2013	10,237,000
2014	1,737,000
2015	1,561,000
2016	1,561,000
Thereafter	5,197,000
Total	$ 142,998,000
Physical commodity requirements utilization period (in years)	3
Electricity purchase commitment
Company's commitments for agreements with take or pay or other similar commitment provisions
Annual "interruptible service" hours at Flat Roll Division	160

Represents the outstanding construction related commitments related to ongoing construction projects.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Represents the number of complaints received that were not brought on behalf of a class consisting of all direct purchasers of steel products.

+ References

No definition available.

+ Details

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- Definition

Number of other steel manufacturing companies which were served with a class action antitrust complaint, filed in the United States District Court.

+ References

No definition available.

+ Details

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- Definition

Maximum annual "interruptible service" hours allowed in electricity agreement at one of company's divisions.

+ References

No definition available.

+ Details

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- Definition

Represents the usage period for physical commodity requirements.

+ References

No definition available.

+ Details

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- Definition

Represents the usage period for commodity transportation requirements.

+ References

No definition available.

+ Details

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- Definition

Represents the utilization period for physical commodity requirements.

+ References

No definition available.

+ Details

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Namespace Prefix:	stld_
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- Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid in more than four and within five years from the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 7

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid within one year of the balance sheet date.

+ References

+ Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid in more than three and within four years from the balance sheet date.

+ References

+ Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid in more than one and within two years from the balance sheet date.

+ References

+ Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid in more than two and within three years from the balance sheet date.

+ References

+ Details

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- Definition

The amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation as of the balance sheet date.

+ References

+ Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid after five years from the balance sheet date.

+ References

No definition available.

+ Details

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- Details

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